Question 301 of 504
CryptographyeasyMultiple ChoiceObjective-mapped

Quick Answer

The correct answer is ECDHE, which stands for Elliptic Curve Diffie-Hellman Ephemeral. This component of the cipher suite provides perfect forward secrecy because it generates a unique, temporary session key for each TLS handshake, and that ephemeral key is discarded immediately after the session ends. If an attacker later compromises the server’s long-term private key, they cannot decrypt past session traffic, since the discarded ephemeral keys are irretrievable. On the SSCP exam, this concept tests your understanding of secure key exchange protocols and how PFS protects archived communications. A common trap is confusing ECDHE with static ECDH, which lacks PFS because it uses a fixed key. Remember the memory tip: the “E” in ECDHE stands for “Ephemeral,” which means “temporary”—if the key is temporary, past sessions stay secure.

SSCP Cryptography Practice Question

This SSCP practice question tests your understanding of cryptography. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

Exhibit

Refer to the exhibit.
OpenSSL> s_client -connect example.com:443
...
New, TLSv1.2, Cipher is ECDHE-RSA-AES256-GCM-SHA384
Server public key is 2048 bit
...

Refer to the exhibit. Which component of the cipher suite provides perfect forward secrecy?

Question 1easymultiple choice
Full question →

Exhibit

Refer to the exhibit.
OpenSSL> s_client -connect example.com:443
...
New, TLSv1.2, Cipher is ECDHE-RSA-AES256-GCM-SHA384
Server public key is 2048 bit
...

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

ECDHE

ECDHE (Elliptic Curve Diffie-Hellman Ephemeral) provides perfect forward secrecy (PFS) because it generates a unique, ephemeral session key for each TLS session. If the long-term private key is compromised, past session keys cannot be derived, as the ephemeral keys are discarded after use. This is defined in RFC 4492 and is a core property of ephemeral Diffie-Hellman key exchange.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • ECDHE

    Why this is correct

    ECDHE uses ephemeral keys, ensuring forward secrecy.

    Related concept

    Read the scenario before looking for a memorised answer.

  • TLS 1.2

    Why it's wrong here

    The protocol version does not guarantee forward secrecy.

  • AES256-GCM

    Why it's wrong here

    AES is the symmetric encryption algorithm, not related to forward secrecy.

  • SHA384

    Why it's wrong here

    SHA384 is the hash for MAC, not for key exchange.

Common exam traps

Common exam trap: answer the scenario, not the keyword

ISC2 often tests the distinction between the protocol version (TLS 1.2) and the cipher suite components that actually implement PFS, leading candidates to incorrectly select TLS 1.2 because they associate it with modern security features.

Detailed technical explanation

How to think about this question

Perfect forward secrecy relies on ephemeral Diffie-Hellman (DHE or ECDHE) where each session generates a fresh key pair; the private key is stored only in memory and destroyed after the session ends. Even if an attacker records all encrypted traffic and later obtains the server's long-term RSA or ECDSA private key, they cannot decrypt past sessions because the session key was derived from the ephemeral keys. In practice, this is critical for compliance with standards like PCI DSS and for protecting historical data against future key compromise.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A developer is choosing between AES-256 (symmetric) and RSA-2048 (asymmetric) for encrypting a large file that will be sent to a partner. Symmetric encryption is fast but requires key exchange; asymmetric is slower but solves the key distribution problem. A hybrid approach — encrypt the file with AES, encrypt the AES key with RSA — is standard. Questions like this test whether you understand when each approach applies.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this SSCP question test?

Cryptography — This question tests Cryptography — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: ECDHE — ECDHE (Elliptic Curve Diffie-Hellman Ephemeral) provides perfect forward secrecy (PFS) because it generates a unique, ephemeral session key for each TLS session. If the long-term private key is compromised, past session keys cannot be derived, as the ephemeral keys are discarded after use. This is defined in RFC 4492 and is a core property of ephemeral Diffie-Hellman key exchange.

What should I do if I get this SSCP question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 30, 2026

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This SSCP practice question is part of Courseiva's free ISC2 certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SSCP exam.